A videomicroscopic investigation of coupled reversible flocculation and coalescence at singlet-doublet equilibrium in an O/W emulsion of low density contrast

Video enhanced microscopy (VEM) enables direct investigation of dilute emul sions. A practical and effective preparative technique utilizes microslides , which are flat, rectangular microcapillaries made from borosilicate glass . Experimental difficulties due to droplet sedimentation and droplet-micros lide wall interaction can be drastically reduced, even eliminated, by the u se of low density contrast emulsions, i.e. emulsions where the densities of the dispersed and continuous phases are not very different. The dichlorode cane (DCD)-in-water emulsion is an example of such a system. This system ca n as such be used for measurement of the time of the elementary act of coal escence, calculated from the evolution in the droplet size distribution. Th e developing distributions can be determined through automated VEM. In this paper we discuss the perspective for elaboration of a standard meth od for the determination of an averaged time for the elementary act of coal escence. The experimental basis is automated measurement of the time depend ence of the droplet size distribution, as applied to dilute DCD/w emulsions at singlet-doublet equilibrium.